The invention relates to the area of cancer diagnostics and therapeutics. More particularly, the invention relates to detection and remediation of the loss and or alteration of wild-type p53 genes from tumor tissues.
Recent studies have elucidated several genetic alterations that occur during the development of colorectal tumors, the most common of which are deletions of the short arm of chromosome 17 (17p). While some genetic alterations such as RAS gene mutations, appear to occur relatively early during colorectal tumor development, chromosome 17p deletions are often late events associated with the transition from the benign (adenomatous) to the malignant (carcinomatous) state. See Vogelstein et al., New England Journal of Medicine, Vol. 319, p525, 1988.
Because carcinomas are often lethal, while the precursor adenomas are uniformly curable, the delineation of the molecular events mediating this transition are of considerable importance. The occurrence of allelic deletions of chromosome 17p in a wide variety of cancers besides those of the colon, including those of the breast and lung, further emphasizes the importance of genes residing on chromosome 17p in the neoplastic process. Because allelic deletions have been reported to encompass a large area of chromosome 17p, there is a need in the art for defining the particular genetic region which is responsible for the neoplastic progression.
It is an object of the present invention to provide a method for diagnosing a neoplastic tissue of a human.
It is another object of the invention to provide a method of supplying wild-type p53 gene function to a cell which has lost said gene function.
It is yet another object of the invention to provide a kit for determination of the nucleotide sequence of the p53 gene by using the polymerase chain reaction.
It still another object of the invention to provide a nucleic acid probe for detection of mutations in the human p53 gene.
These and other objects of the invention are provided by one or more of the embodiments which are described below. In one embodiment of the present invention a method of diagnosing a neoplastic tissue of a human is provided comprising: isolating from a human a tissue suspected of being neoplastic; and detecting loss of wild-type p53 genes or their expression products from said tissue, said loss indicating neoplasia of the tissue.
In another embodiment of the present invention a method is provided for supplying wild-type p53 gene function to a cell which has lost said gene function by virtue of a mutation in the p53 gene, comprising: introducing a wild-type p53 gene into a cell which has lost said gene function such that said wild-type gene is expressed in the cell.
In yet another embodiment a kit is provided for determination of the nucleotide sequence of the p53 gene by polymerase chain reaction. The kit comprises: a set of pairs of single stranded DNA primers, said set allowing synthesis of all nucleotides of the p53 gene coding sequences.
In still another embodiment of the invention a nucleic acid probe is provided which is complementary to human wild-type p53 gene sequences and which can form mismatches with mutant p53 genes, thereby allowing their detection by enzymatic or chemical cleavage or by shifts in electrophoretic mobility.
The present invention provides the art with the information that the p53 gene is, in fact, the target of both deletional and point mutational alterations on chromosome 17p which are associated with the process of tumorigenesis. This information allows highly specific assays to be done to assess the neoplastic status of a particular tumor tissue as well as the performance of therapeutic anti-cancer methods.